Climate change is one of the most pressing problems facing the global community. Although most states agree that climate change is occurring and is at least partly the result of humans' reliance on fossil fuels, managing a changing global climate is a formidable challenge. Underlying this challenge is the fact that states are sovereign, governed by their own laws and regulations. Sovereignty requires that states address global problems such as climate change on a voluntary basis, by negotiating international agreements. Despite a consensus on the need for global action, many questions...